Missing debug package(s), you should install: x11-server-debug-1.9.1-2mdv2011.0.x86_64
(gdb) bt
#0  0x0000003f27632075 in raise () from /lib64/libc.so.6
#1  0x0000003f27633806 in abort () from /lib64/libc.so.6
#2  0x000000000046390e in OsAbort ()
#3  0x000000000046f3f7 in ddxGiveUp ()
#4  0x000000000045fe62 in ?? ()
#5  0x000000000046007e in FatalError ()
#6  0x00000000004610de in ?? ()
#7  <signal handler called>
#8  0x00007f93ba9be132 in dixGetPrivateAddr (client=0x0, entry=0x20eaac0) at /usr/include/xorg/privates.h:123
#9  dixLookupPrivate (client=0x0, entry=0x20eaac0) at /usr/include/xorg/privates.h:165
#10 ListDelDRI2ClientEvents (client=0x0, entry=0x20eaac0) at radeon_dri2.c:499
#11 0x00007f93ba9be5d1 in radeon_dri2_schedule_swap (client=0x27e7100, draw=0x20b4e80, front=0x20b5360, back=0x20b50b0, target_msc=0x7fff2292db78, divisor=0, remainder=0, func=0x7f93badf9680, data=0x20b4e80)
    at radeon_dri2.c:988
#12 0x00007f93badf8aba in DRI2SwapBuffers () from /usr/lib64/xorg/modules/extensions/libdri2.so
#13 0x00007f93badf9ea5 in ?? () from /usr/lib64/xorg/modules/extensions/libdri2.so
#14 0x000000000042d8d1 in ?? ()
#15 0x00000000004218ce in _start ()